1. Field of the Invention
The present invention relates generally to electronic modular structures. More particularly, the invention relates to tool-actuated ejectors for extracting modular components plugged into electronic devices.
2. Description of the Prior Art
Modular construction techniques are widely used to manufacture a variety of electronic equipment, such as personal computers (PC's), peripheral devices, networking equipment, and the like. With modular construction, manufacturers can assemble, at markedly low cost, a variety of systems using different combinations of pre-assembled modular circuits. The versatility of modular construction also permits computer vendors to construct complex systems having varying optional functions and capabilities by simply adding, at a point of sale, modular components to basic units initially provided by manufacturers. In addition, modular construction allows an end user with only moderate skill to repair, upgrade and/or re-configure electronic equipment. In most instances, replacing and/or adding modular electronic circuits to a basic system requires no more than a simple screwdriver and minimal mechanical skill.
Manufacturers design many modular circuits as printed circuit boards (PCB's). Conventional PCB's, frequently called circuit boards or cards, normally carry an electrical connector that mates with a matching connector mounted on a separate component, such as another PCB (e.g., a motherboard). The matching connectors are ordinarily of the plug-in type wherein protruding conductive pins and/or edge contacts of a male connector mate with corresponding electrical sockets of a female connector. The sockets usually include resilient or spring-loaded electrical contacts that tightly grip the protruding edge contacts or pins of the male connector.
During manual installation of most circuit boards, guides and/or grooves located on or within a casing help position and guide the boards as their connectors plug into appropriate connectors within the casing. The restrictive forces exerted by the electrical contacts of a typical connector socket, in addition to any other forces exerted by guides and/or mounting structures, generally provide sufficient mechanical support to hold a circuit board in place. In some situations, however, manufacturers need to add special board fasteners to help secure circuit boards. The use of fasteners becomes especially important when parts of a modular component are exposed to the exterior of a casing. For instance, many circuit boards, such as expansion boards, mount within individual expansion slots having openings located in the front, side or back panels of a casing. In those instances, screws, springs, detents and the like often secure the circuit boards to the casing or to a fixed support located within the casing.
When manually removing an ordinary circuit board from a slot, an individual first removes any special fasteners, and then simply grasps the board with a hand and pulls the board free. Individuals normally have no problem in manually overcoming the restricting forces exerted by standard plug-in connectors, guides and similar supports. However, the extraction forces for some plug-in connectors are too large for most individuals to safely perform manual removal of a circuit board. When applying excessive extraction forces to a plug-in connector, a user will often twist or bend a board or a component, causing damage to pin and socket contacts or other delicate structures. In other instances, where circuit boards mount in crowded spaces, neighboring circuit boards often block a user's hand or otherwise prevent the user from applying sufficient extraction force to a circuit board. To avoid these and similar problems, some manufacturers provide mechanical ejectors that individuals can manually actuate to help extract a plugged-in circuit board or other component.
The following United States patents illustrate prior art ejectors for circuit boards and similar modular electronic components: McNiece et al, U.S. Pat. No. 4,083,616 issued Apr. 11, 1978; Miller et al, U.S. Pat. No. 4,603,375 issued Jul. 29, 1986; and Blankenship, U.S. Pat. No. 4,999,744 issued Mar. 12, 1991. The ejectors of these patents generally comprise levered cams that individuals operate manually to perform a safe, controlled extraction of a circuit board or other component. Specifically, a user manually operates a lever while an attached cam exerts a force in an appropriate direction at a suitable safe point on a component being extracted. Essentially, the combination of the lever and the cam provide a user with sufficient mechanical advantage so that the user can easily overcome the particular extraction force required to unplug a component.
Although currently available ejectors have served the purpose, they have not proved entirely satisfactory when an ejector and/or its associated modular component mounts on the exterior of a casing or in unprotected areas within a casing. Manufacturers have found that exposed surfaces of an ejector often present a hazard to equipment and/or personnel using the equipment. For example, users, onlookers or other individuals may inadvertently actuate an exposed ejector, thereby unwittingly displacing or damaging its associated component. More seriously, accidental ejection of and/or tampering with some electronic components can cause injury from electric shock. Thus, those concerned with the development of modular electronic equipment have recognized the need for improving such equipment to forestall accidental actuation of an ejector and discourage tampering with potentially hazardous electronic devices.